The impact of incidental identification on the stage at presentation of lower gastrointestinal carcinoids

Background: Over the past 3 decades, there has been a significant increase in the incidence of gastrointestinal carcinoid tumors in the United States. Incidentally discovered carcinoids in the lower gastrointestinal tract have probably contributed to this increase. In this study we aimed to compare the clinicopathologic characteristics of incidentally discovered carcinoids of the small and large bowel with those identified as a result of symptoms. Study Design: We performed a retrospective review of 58 consecutive patients with nonappendiceal gastrointestinal carcinoids: 30 small bowel and 28 large bowel. We compared asymptomatic patients with lower gastrointestinal tract carcinoids identified by routine colonoscopy with those identified as a result of symptoms. Results: Twenty-eight (48.3%) incidentally identified carcinoids (15 small bowel and 13 large bowel) were compared with 30 (51.7%) symptomatic carcinoids. Incidental ileal carcinoids were similar in size (mean ± SD, 1.3 ± 0.61 vs 1.7 ± 1.13, p = 0.45) and incidence of lymph node metastases (12 in 15 vs 9 in 15, p = 0.43) to symptomatic ileal carcinoids. However, incidental ileal carcinoids had a lower incidence of distant metastases (1 in 15 vs 7 in 15, p = 0.035) compared with symptomatic ileal carcinoids. There was no difference in tumor size, extent of lymph node metastases, or distant metastases between incidental and symptomatic large bowel carcinoids. Conclusions: Ileal carcinoids identified at screening colonoscopy are associated with a significantly decreased incidence of distant metastases compared with those identified after development of symptoms, despite similar size and extent of lymph node metastases. However, incidental large bowel carcinoids appear to have similar staging to those identified as a result of symptoms.